Skill with inputs

How do you get a skill to register required inputs. When trying to create a custom skill like the weather skill that requires specific user input fields, examples I’ve found add definitions to their skill manifest, but following them always gives the “The manifest is incompatible Definition required property is not supported” error.

Error

    {
        "Test":
        {
            "type": "event",
            "name": "Test",
        
            "value": 
            {
                "$ref": "#/definitions/bookingInfo"
            }
        },
        "conversationUpdate": { "type": "conversationUpdate" }
    },
    
    "definitions" :
    {
        "bookingInfo":
        {
            "type": "object",
            "required": [ "origin" ],
            "properties": 
            {
                "origin": 
                {
                    "type": "string",
                    "description": "this is the origin city for the flight"
                },
                "destination":
                {
                    "type": "string",
                    "description": "this is the destination city for the flight"
                },
                "date": 
                {
                    "type": "string",
                    "description": "The date for the flight in YYYY-MM-DD format"
                }
            }
        }
    }```